Overview

• SWS: 4, ECTS: 8.0, (for 10.0 , e.g. Media Informatics, you have to write a detailed project report)
  
• Lecturer: Prof. Dr. Klaus Wehrle
• Teaching Assistant: Dirk Thissen, Ismet Aktas
• Student website with course material: comming soon

Important dates

• Weekly meetings: every friday at 15:00 in room 4108b
• Kick-off meeting: 23.10.2009 at 15:00 in room 4108b (Besprechungsraum I4)
  
• Registration: https://web-info8.informatik.rwth-aachen.de/apse
• Time line:
• Part I: mobile communication system engineering basics: October, November
• Part II: individual projects: December to February, maybe March
• Presentation of results: end of February, possibly in lecture-free time

Contents of the UMIC mobile communication systems engineering lab

Classical network protocol stacks are organized in layers. (1) The physical layer is concerned with transmitting raw bits via some medium, such as cooper cables, fiber channel, or radio waves. (2) The data link layer transmits data between adjacent hosts. It typically also adds checksums for detecting errors and manages the medium access. (3) The network layer realizes end-to-end connectivity over several intermediate nodes while the (4) transport layer typically performs congestion control, reliable-, and in-order delivery of packets. These layers are strictly separated and can only communicate over a concise interface by passing packets up and down the stack.

In principle, all these layers can provide their functionality without interaction across the layers, which works well in wired and static environments. However, but today’s networks not only consist of wired links but also include wireless networks. Wireless and mobile communication pose new challenges to the design of the today’s communication sub-systems. Rapidly changing network conditions that are largely affected by host mobility and environmental influences require a more sophisticated interaction between protocols than the layered architecture offers. One promising way to dealing with these shortcomings is the exchange of information across layers. Systematic cross-layer communication can significantly reduce energy consumption and improve performance as well as service quality of the whole protocol stack.

For example, when switching base stations, short interrupts and packet loss are likely. As the congestion control mechanisms of transport-layer protocols, such as TCP, are not aware of the situation as this information is data-link-layer specific. Hence, the transport layer will interpret this lag and loss as congestion and will throttle its sending rate, accordingly. Cross-layer communication could enable a smart TCP to adjust its congestion control algorithm to preserve the sending rate, and thus, enabling TCP to prevent bandwidth drops.

Organization

The lab is split into two parts. The first part covers the theoretic background of mobile communication, the layered architecture, and cross-layer approaches. The lessons are accompanied by practical exercises that will familiarize you with the concepts, interfaces, and tools required to get you started.

In the second part of the lab, groups of two to three students will focus on different lab projects focusing on several of the following topics:

• The UMIC excellence cluster
  
• Network stacks for mobile devices
• Protocols and frameworks for host mobility
• Handover process and optimization
• Detection and smart selection of available base stations
• Sensing, monitoring and processing of network conditions and protocol states
• Smart decision-making based on information from different layers

Moreover, we encourage you to contribute your own ideas as lab-projects as long as they fit into the general theme of mobile communication systems engineering.

What you will learn?

You will gather experience in working with…

• ... projects in the UMIC excellence initiative at RWTH Aachen University
  
• … the Linux networking stack
• … wireless networking
• … embedded Linux devices
• … kernel- and user-space programs
• … network analysis tools

The broad goal of this lab is to create a framework for optimized handovers between base stations that combines knowledge from various layers to achieve smart, fast, and seamless handovers between base stations and Wi-Fi access points.

With which tools you will get experience?

You will learn and work with several tools like:

• SVN
• TCPdump, Wireshark
• Scratchbox, Doxygen, OpenWRT
• GDB, Valgrind, LINT/SPLINT
• Netfilter, openWRT
• Shell

What should you bring?

Now, this is a hands-on lab on distributed systems. Thus, you should bring some knowledge in this area.
The requirements are:

• Prediploma or equivalent (e.g. be in a masters program)
• Some lectures in the area of Distributed Systems, Communication Systems and/or Mobile Communication
• Taking (or having taken) our CSE lecture "Communication Systems Engineering" is helpful
• Knowledge of C is obligatory!
• Knowledge of socket programming is helpful but not obligatory
• Strong interest and willingness to contribute time to an interesting lab project